Infecciosas Flashcards
1
Q
What percentage of patients with a reported allergy will tolerate penicillin?
A
Approx. 85–90% of patients
This suggests that many patients may not have a true allergy.
2
Q
What should be included in an allergy evaluation for penicillin?
A
An epicutaneous (prick) test and, if negative, an intradermal test
These tests help assess true penicillin allergy.
3
Q
What qualifies a patient for desensitization to penicillin?
A
A possible history of an allergic reaction
This applies even if allergy evaluation is not possible.
4
Q
When should desensitization be initiated for penicillin?
A
Regardless of the allergen test report
This is due to the poor sensitivity of allergen tests.
5
Q
What is a significant risk associated with relying on a single allergen test report?
A
The risk of anaphylaxis
This emphasizes the need for caution in allergy assessments.
6
Q
Fill in the blank: Allergy evaluation should be conducted in patients with any history suggesting an _______.
A
allergy
This underlines the importance of thorough patient histories.
7
Q
What is the most common trigger of bacteremia leading to IE?
A
Dental procedures, surgery, distant primary infections, and nonsterile injections
8
Q
What are the two types of infective endocarditis based on the speed of development?
A
Acute and subacute
9
Q
What organism is usually responsible for acute bacterial endocarditis?
A
Staphylococcus aureus
10
Q
What is the typical cause of subacute bacterial endocarditis?
A
Viridans streptococci
11
Q
Who is most commonly affected by subacute bacterial endocarditis?
A
Individuals with preexisting damage to heart valves, congenital heart defects, and/or prosthetic valves
12
Q
List some clinical features of infective endocarditis.
A
- Fatigue
- Fever
- Chills
- Malaise
- New or changed heart murmur
- Signs of heart failure
- Manifestations of organ damage (e.g., glomerulonephritis, septic embolic stroke)
13
Q
What are the 2023 Duke-ISCVID criteria used for?
A
To assess the likelihood of infective endocarditis
14
Q
What is the initial treatment for infective endocarditis?
A
Empiric IV antibiotics, adjusted based on blood culture results
15
Q
Why is distinguishing between native and prosthetic valve IE important?
A
It allows for more tailored treatment
16
Q
When may surgery be necessary in cases of infective endocarditis?
A
In complex cases such as valve perforation
17
Q
Is prophylaxis for infective endocarditis recommended?
A
Yes, in specific circumstances like congenital heart disease during certain dental procedures
18
Q
True or False: Infective endocarditis is typically non-fatal if left untreated.
A
False
19
Q
What is indicated prior to certain procedures with a high risk of bacteremia in patients with high-risk cardiac features?
A
Prophylaxis
Prophylaxis is important to prevent infective endocarditis (IE) in susceptible patients
20
Q
List the cardiac risk factors requiring infective endocarditis prophylaxis.
A
- Presence of prosthetic cardiac valve or material
- History of endocarditis
- Certain types of congenital heart disease (CHD)
- Valvulopathy in cardiac transplant recipients
Specific CHD types include unrepaired cyanotic CHD, repaired CHD within 6 months of repair, and repaired CHD with residual post-operative shunt or regurgitation
21
Q
What are some procedures that require infective endocarditis prophylaxis in patients at risk?
A
- Dental procedures including tooth extraction and routine dental cleaning
- Invasive procedures involving respiratory tract or infected tissue
- Placement of a CIED
- Surgical placement of prosthetic cardiac or intravascular material
CIED stands for cardiac implantable electronic device
22
Q
What is the common prophylaxis regimen for patients without a penicillin allergy prior to dental procedures?
A
- Amoxicillin
- Ampicillin
- Cefazolin
The specific dosage is not provided in the text
23
Q
What is the recommended prophylaxis regimen for patients with a penicillin allergy prior to dental procedures?
A
- Macrolide (e.g., azithromycin)
- Doxycycline
The specific dosage for these medications is not provided in the text
24
Q
What is the recommended prophylaxis regimen prior to CIED placement?
A
Cefazolin
The specific dosage is not provided in the text
25
True or False: Infective endocarditis prophylaxis is routinely recommended prior to nondental procedures.
False
## Footnote
IE prophylaxis is not routinely recommended unless infected tissue is present
26
Fill in the blank: Pathogen-specific agents may be indicated depending on the _______.
[site of the procedure]
## Footnote
This indicates that the choice of prophylactic agent can vary based on the type of procedure being performed
27
What is schistosomiasis?
A parasitic disease caused by schistosomes, a type of trematode
## Footnote
Schistosomiasis is transmitted through contact with parasite-infested water.
28
How does infection occur in schistosomiasis?
When skin comes into contact with parasite-infested water
## Footnote
This typically happens in freshwater bodies where schistosomes are present.
29
What is swimmer's itch?
A pruritic maculopapular rash caused by initial skin penetration by schistosomes
## Footnote
This rash is an early manifestation of schistosomiasis.
30
What is acute schistosomiasis syndrome also known as?
Katayama fever
## Footnote
This syndrome occurs during parasite migration through the bloodstream.
31
What are the symptoms of acute schistosomiasis syndrome?
* Fever
* Cough
* Angioedema
## Footnote
These symptoms reflect an acute inflammatory response to the parasites.
32
What does chronic infection by schistosomes cause?
A granulomatous inflammatory response to schistosome eggs
## Footnote
The severity and symptoms vary based on the location of the infection.
33
What are the manifestations of genitourinary schistosomiasis?
* Hematuria
* Dysuria
## Footnote
Long-standing infection increases the risk of bladder cancer.
34
What are the symptoms of intestinal schistosomiasis?
* Diarrhea
* Abdominal pain
## Footnote
Symptoms can vary based on the severity of the infection.
35
What can hepatosplenic schistosomiasis lead to?
* Hepatosplenomegaly
* Portal hypertension
## Footnote
These conditions result from chronic schistosomiasis affecting the liver and spleen.
36
How is schistosomiasis diagnosed?
By identifying eggs on microscopic examination of stool or urine
## Footnote
This is the primary method for confirming the presence of schistosomes.
37
What is the treatment for acute schistosomiasis syndrome?
Symptomatic treatment with glucocorticoids
## Footnote
Glucocorticoids help manage the inflammatory response.
38
What is the mainstay of treatment for parasite eradication in schistosomiasis?
Praziquantel
## Footnote
Praziquantel is effective against all forms of schistosomiasis.
39
What is infectious gastroenteritis?
An inflammation of the gastrointestinal tract caused by various pathogens.
40
What are the most common viral causes of infectious gastroenteritis?
Norovirus, rotavirus, enteric adenovirus.
41
Name some bacterial causes of infectious gastroenteritis.
* Campylobacter
* Salmonella
* Shigella
* Yersinia
* Vibrio cholerae
* Diarrheagenic Escherichia coli
* Clostridioides difficile
42
What types of pathogens can cause infectious gastroenteritis?
* Viruses
* Bacteria
* Fungi
* Parasites (protozoans, helminths)
43
What are common transmission routes for infectious gastroenteritis?
* Fecal-oral
* Foodborne
* Waterborne
44
What is crucial for preventing infectious gastroenteritis?
Education on food and water hygiene.
45
List some clinical features of mild infectious gastroenteritis.
* Abdominal pain
* Diarrhea
* Nausea
* Vomiting
46
What are some severe clinical features of infectious gastroenteritis?
* Sepsis
* Intense abdominal pain
* Significant dehydration from severe diarrhea and/or vomiting
47
In cases of mild gastroenteritis, what is usually required?
Supportive therapy, such as oral rehydration and antiemetics.
48
When might stool cultures and empiric antibiotic therapy be considered?
In patients with severe gastroenteritis and/or risk factors for complicated disease.
49
True or False: Infectious gastroenteritis is always severe and requires hospitalization.
False
50
Fill in the blank: The fecal-oral route is a common transmission method for _______ gastroenteritis.
[infectious]
51
What is the typical course of infectious gastroenteritis?
Usually self-limiting.
52
What additional topics are covered separately regarding infectious gastroenteritis?
Infectious gastroenteritis in children and Clostridioides difficile infection.
53
What is anthrax?
A rare infectious disease caused by Bacillus anthracis.
54
What type of bacterium causes anthrax?
Gram-positive spore-forming bacterium.
55
Where is Bacillus anthracis typically found?
In soil.
56
How do humans usually become infected with anthrax?
Contact with infected livestock or infected animal products.
57
What are examples of infected animal products that can transmit anthrax?
* Wool
* Meat
58
What are the three distinct clinical syndromes of anthrax based on the route of entry?
* Inhalation anthrax
* Cutaneous anthrax
* Gastrointestinal anthrax
59
Which form of anthrax is the most common?
Cutaneous anthrax.
60
What is the initial presentation of cutaneous anthrax?
A papular lesion.
61
What does the papular lesion of cutaneous anthrax eventually become?
A necrotic eschar.
62
What are the symptoms of inhalation anthrax?
* Fever
* Acute, nonproductive cough
* Retrosternal chest pain
* Pleural effusion
63
What severe condition does inhalation anthrax result in?
Hemorrhagic mediastinitis.
64
What symptoms are associated with gastrointestinal anthrax?
* Gastrointestinal ulceration
* Hematemesis
* Bloody diarrhea
65
Is gastrointestinal anthrax common?
No, it is very rare.
66
How is the diagnosis of anthrax confirmed?
Microscopic evidence of B. anthracis.
67
What is the mortality rate of anthrax without treatment?
High.
68
What types of antibiotics can increase survival in anthrax patients?
* Fluoroquinolones
* Linezolid (oxazolidinonas)
* Meropenem (betalactam)
69
Which form of anthrax has a better prognosis, cutaneous or inhalation?
Cutaneous anthrax.
70
Fill in the blank: Anthrax can be weaponized for _______.
[biological warfare/terrorism]
71
True or False: Cutaneous anthrax is the least common form of anthrax.
False.
72
What is schistosomiasis?
A parasitic disease caused by schistosomes, a type of trematode.
73
How does infection with schistosomiasis occur?
When skin comes into contact with parasite-infested water.
74
What is the initial skin reaction to schistosomiasis infection called?
Swimmer's itch.
75
What are the clinical manifestations of acute schistosomiasis syndrome?
Fever, cough, and angioedema.
76
What is another name for acute schistosomiasis syndrome?
Katayama fever.
77
What type of inflammatory response is caused by chronic schistosomiasis?
Granulomatous inflammatory response to schistosome eggs.
78
What symptoms are associated with genitourinary schistosomiasis?
Hematuria and dysuria.
79
What long-term risk is associated with genitourinary schistosomiasis?
Increased risk of bladder cancer.
80
What symptoms may indicate intestinal schistosomiasis?
Diarrhea and abdominal pain.
81
What complications can arise from hepatosplenic schistosomiasis?
Hepatosplenomegaly and/or portal hypertension.
82
How is schistosomiasis diagnosed?
By identifying eggs on microscopic examination of stool or urine.
83
What is the treatment for acute schistosomiasis syndrome?
Symptomatic treatment with glucocorticoids.
84
What is the mainstay of treatment for parasite eradication in schistosomiasis?
Praziquantel.
85
What is the most likely diagnosis in a patient with recent antibiotic use, watery diarrhea, fever, and leukocytosis with left shift?
Clostridioides difficile infection
## Footnote
Symptoms of C. difficile infection typically begin during or within 21 days of an antibiotic course.
86
What antibiotic is a known causative agent of C. difficile infection?
Clindamycin
87
What is the recommended first-line agent for the treatment of an initial episode of severe C. difficile infection?
Vancomycin
88
Under what conditions is C. difficile disease considered severe?
If the patient has systemic toxicity, a peripheral leukocyte count >14,000 per mm3, or a high-risk condition
## Footnote
High-risk conditions include renal insufficiency and intensive care status.
89
What alternative antibiotic may be considered for less severe cases of C. difficile infection?
Metronidazole
90
What new antibiotic is recommended as first-line therapy for adults (≥18 years) with C. difficile infection?
Fidaxomicin (macrolido)
91
When is fidaxomicin recommended for children?
In the setting of multiple recurrent infections
92
What key learning point is associated with pediatric patients and recent antibiotic use?
The onset of watery diarrhea, fever, and leukocytosis is concerning for Clostridioides difficile colitis, and empiric therapy with vancomycin should be initiated.
93
What is the recommended age range for receiving the HPV vaccine?
11–26 years of age
## Footnote
The HPV vaccine is recommended for all unvaccinated individuals within this age range.
94
Why should this patient be offered the HPV vaccine?
He does not have any documentation of having received it
## Footnote
Documentation of previous vaccination is necessary to determine if a patient should receive the vaccine.
95
What should all mothers with HIV be counseled about?
The risks of HIV transmission through breast milk
96
In resource-rich areas, what should women breastfeeding with incompletely suppressed viral loads or low CD4-cell counts be counseled to do?
Avoid breastfeeding
97
What type of counseling should clinicians engage in regarding infant feeding?
Evidence-based counseling to support shared decision-making
98
What is the risk of HIV transmission through breastfeeding for women with virologic suppression during pregnancy?
Low (<1%) risk
99
What should women who want to eliminate the risk of HIV transmission completely be counseled to use for infant feeding?
Formula or donor milk from a milk bank
100
In low-resource areas, what is recommended for breastfeeding mothers with HIV?
Combination antiretroviral therapy
101
What should infants of breastfeeding mothers with HIV receive in low-resource areas?
A 6-week course of nevirapine
102
What outweighs the potential adverse effects of antiretroviral medications in breast milk in low-resource areas?
The benefits of breast milk in the absence of a safe water supply
103
What maternal viral load indicates a high risk for perinatal HIV transmission?
>1000 copies
104
What other infectious contraindications to breastfeeding exist?
Maternal human T-cell lymphotropic virus type 1 or 2, untreated brucellosis, active untreated tuberculosis, infected lesions on the breast
105
When can women with active tuberculosis resume breastfeeding?
After being treated for at least 2 weeks and are no longer infectious
106
Fill in the blank: In areas where infant formula is accessible, affordable, and free, women with HIV should be counseled to _______ if their CD4-cell count is low.
avoid breastfeeding
107
True or False: The risk of HIV transmission through breastfeeding is zero for women with virologic suppression.
False
108
What is the most common cause of acute community-acquired bloody diarrhea in febrile patients?
Enteric infections such as Salmonella, Shigella, Campylobacter, or Shiga toxin-producing Escherichia coli (STEC)
## Footnote
These pathogens are often responsible for bloody diarrhea in febrile patients.
109
Why is it important to correctly diagnose infection with STEC?
For public health reasons and because antibiotic treatment may increase the risk for hemolytic-uremic syndrome
## Footnote
Hemolytic-uremic syndrome is a serious complication associated with STEC infections.
110
What type of test should be used to identify STEC in stool samples?
An enzyme immunoassay for Shiga toxin
## Footnote
This method is preferred because stool culture cannot identify non-O157 strains.
111
What percentage of STEC infections are accounted for by non-O157 strains?
About 40%
## Footnote
Non-O157 strains are significant contributors to STEC infections.
112
What should be included in the evaluation of acute community-acquired bloody diarrhea in a patient with no history of antibiotic exposure?
Both a stool culture for enteric pathogens and a non-culture-based immunoassay for Shiga toxin
## Footnote
This dual approach ensures a comprehensive evaluation of potential pathogens.
113
What is the Mycobacterium avium complex known for?
It is the most frequent cause of pulmonary infection due to nontuberculous mycobacteria in the United States.
## Footnote
Mycobacterium avium complex is ubiquitous in the environment.
114
Who are the typical patients with isolated pulmonary M. avium complex?
Immunocompetent adults, most commonly with underlying lung disease, or postmenopausal women.
## Footnote
These patients often present with specific symptoms and imaging findings.
115
What symptoms do patients with M. avium complex typically present with?
Chronic cough, fever, and weight loss.
## Footnote
These symptoms can indicate a pulmonary infection.
116
What imaging findings are associated with Mycobacterium avium complex infection in postmenopausal women?
Nodular opacities with bronchiectasis in the right middle lobe.
## Footnote
This presentation is also referred to as Lady Windermere syndrome.
117
What do sputum cultures show in cases of M. avium complex infection?
Acid-fast bacilli.
## Footnote
This finding is typical for infections caused by mycobacteria.
118
Fill in the blank: The most likely cause of chronic cough, fever, and weight loss in an older woman with bronchiectasis and nodular opacities on chest imaging is _______.
Mycobacterium avium complex infection.
119
What does hydrogen peroxide oxidize?
Cell membrane lipids, intracellular proteins, and DNA
## Footnote
Hydrogen peroxide oxidizes these components by forming hydroxyl free radicals.
120
What are the uses of hydrogen peroxide?
Wound disinfection and surface disinfectant
## Footnote
It is commonly used in medical settings and for cleaning purposes.
121
Hydrogen peroxide is active against which types of microorganisms?
Bacteria, yeasts, fungi, viruses, and spores
## Footnote
This broad spectrum of activity makes it effective for various disinfection purposes.
122
True or False: Hydrogen peroxide is only effective against bacteria.
False
## Footnote
Hydrogen peroxide is effective against multiple types of microorganisms.
123
Fill in the blank: Hydrogen peroxide forms _______ free radicals during oxidation.
hydroxyl
## Footnote
These free radicals are highly reactive and contribute to the oxidative damage.
124
What are noninfectious complications related to HIV?
Chronic inflammation from HIV or adverse effects of antiretroviral therapy
## Footnote
Noninfectious complications can arise from the body's response to HIV or the medications used to treat it.
125
What are some complications of antiretroviral therapy?
* Dyslipidemia
* Impaired glucose tolerance
* Osteoporosis
## Footnote
These complications can affect metabolic health and bone density in patients undergoing treatment.
126
What is the effect of all antiretroviral regimens on bone mineral density (BMD)?
All antiretroviral regimens contribute to a loss of BMD
## Footnote
This loss varies among different regimens, with some having a more pronounced effect.
127
Which antiretroviral regimen is associated with a greater decline in BMD?
Tenofovir disoproxil fumarate
## Footnote
This specific formulation has been linked to more significant bone density loss compared to others.
128
How does tenofovir alafenamide compare to tenofovir disoproxil fumarate regarding BMD?
Tenofovir alafenamide has less effect on BMD than tenofovir disoproxil fumarate
## Footnote
This suggests it may be a preferable option for preserving bone density.
129
Who should be screened for osteoporosis according to current guidelines?
* Men aged 50 or older
* Postmenopausal women of any age
* People with a fragility-type fracture
## Footnote
These groups are at higher risk for osteoporosis and should undergo screening.
130
What key learning point is associated with tenofovir disoproxil fumarate use in people with HIV?
It has been associated with both renal disease and osteoporosis
## Footnote
This highlights the importance of monitoring kidney function and bone health in patients receiving this medication.
131
What is critical to obtain in any patient with a possible endovascular focus of infection?
At least two sets of blood cultures
## Footnote
This is crucial before initiating antimicrobial therapy.
132
Who should be consulted for the complete removal of an infected device?
A specialist in electrophysiology
## Footnote
This is recommended to definitively cure the infection and prevent relapse.
133
What is recommended as initial empiric therapy due to oxacillin resistance among isolates?
Vancomycin
## Footnote
This is particularly important for infections near the site of an implanted cardiac electronic device.
134
When should treatment be started in patients with suspected infections?
After blood cultures are obtained
## Footnote
This ensures accurate diagnosis before commencing therapy.
135
What is an essential initial step in evaluating a patient with suspected implanted cardiac-pacemaker infection?
Draw at least two blood cultures
## Footnote
This is particularly important if there are no stigmata of infective endocarditis.
136
What should be done with invasive devices, especially central venous catheters, postoperatively?
They should be removed as soon as possible to minimize the risk for device-associated infections.
## Footnote
Central venous catheters are particularly high-risk devices for infections.
137
What is the recommended action for a patient with fever and positive blood cultures?
Remove the central venous catheter and start intravenous antibiotics while awaiting final blood culture results.
## Footnote
Prompt action is crucial to manage potential infections effectively.
138
What is a common cause of postoperative fever within the first 48 hours?
Cytokine release, transfusion reaction, or drug hypersensitivity.
## Footnote
These causes are typically non-infectious.
139
Which infections are common within the first week after surgery?
Pneumonia and infections associated with central venous or urinary catheters.
## Footnote
Early postoperative infections can significantly impact recovery.
140
When do surgical-site infections typically occur after surgery?
More than a week after surgery.
## Footnote
This timing is critical for diagnosing and managing infections.
141
What are late-onset complications that can arise after surgery?
Infection with Clostridioides difficile, venous thromboembolism, and late-onset central venous catheter-associated infections.
## Footnote
These complications may require different management strategies.
142
Fill in the blank: Postoperative fever is common, and its etiology varies with the time since the operation, with immediate fever usually due to _______.
cytokine release, transfusion reaction, or drug hypersensitivity.
143
True or False: It is unnecessary to remove central venous catheters in patients with fever and positive blood cultures.
False.
## Footnote
Immediate removal is essential to prevent further complications.
144
What is indicative of infection with Neisseria meningitidis?
The finding of gram-negative intracellular diplococci in a patient with clinical features of bacterial meningitis
## Footnote
This finding is crucial for diagnosing bacterial meningitis caused by N. meningitidis.
145
What factors have contributed to the decreasing incidence of N. meningitidis infections?
Routine use of meningococcal vaccine
## Footnote
The vaccination program has significantly reduced the occurrence of these infections.
146
What are the common transmission environments for N. meningitidis?
Close quarters such as summer camps and college dormitories
## Footnote
These environments facilitate the spread of the bacteria through aerosolized oral secretions.
147
Who should receive postexposure chemoprophylaxis for N. meningitidis infection?
Individuals exposed to patients with known or presumed infection, including:
* Those who have had contact with the patient’s oral or respiratory secretions
* Household members, day-care contacts, and those close to the patient
* Travelers sitting next to the index patient on long flights
## Footnote
Close contact increases the risk of transmission and necessitates prophylaxis.
148
What is the first-line chemoprophylaxis for adults exposed to N. meningitidis?
Oral rifampin, oral ciprofloxacin, or parenteral ceftriaxone
## Footnote
Each agent is effective in eliminating nasopharyngeal carriage of the bacteria.
149
What is the effectiveness rate of the first-line chemoprophylaxis agents for N. meningitidis?
90% to 95% effective
## Footnote
These agents are highly effective in preventing the spread of infection.
150
What is the ideal timing for initiating rifampin after exposure to N. meningitidis?
Within 24 hours after exposure
## Footnote
Timely administration is crucial for effectiveness.
151
What is the appropriate dosing regimen for rifampin after exposure?
10 mg/kg (maximum 600 mg) every 12 hours for 2 days
## Footnote
Proper dosing is essential for achieving effective prophylaxis.
152
How is ciprofloxacin or ceftriaxone administered after exposure to N. meningitidis?
As a single dose following exposure
## Footnote
This method simplifies the treatment regimen.
153
What are the most effective measures for the prevention of catheter-associated urinary tract infections (UTIs)?
Avoidance of unnecessary catheterization, sterile technique during catheter placement, early removal of urinary catheters
## Footnote
These measures are crucial for reducing the risk of UTIs in patients with catheters.
154
When should catheters be removed for patients undergoing surgery not involving the urinary tract?
As soon as possible, preferably within 24 hours postoperatively
## Footnote
Timely removal of catheters is essential to minimize infection risk.
155
Fill in the blank: The early removal of urinary catheters is recommended when they are no longer _______.
indicated
## Footnote
This practice helps prevent infections.
156
True or False: Sterile technique during catheter placement is a recommended measure for preventing catheter-associated UTIs.
True
## Footnote
Using a sterile technique is vital for infection control.
157
What is the common cause of fever in children?
Self-limited viral illness or signs and symptoms consistent with a bacterial illness
158
What key history elements should be included when evaluating a child with fever?
Onset, duration, height of fever, associated symptoms, irritability or lethargy, known sick contacts, medical history, immunization status, travel history
159
What is the goal in evaluating a patient with fever?
To rule out an occult bacterial source of infection
160
Name some occult bacterial sources of infection to consider in a febrile child.
* Acute otitis media
* Urinary tract infection
* Bacteremia
* Meningitis
* Osteomyelitis
161
What should be performed alongside a thorough history in evaluating fever?
A thorough physical examination and supporting laboratory tests
162
What conditions should be considered in a young child with fever and rash?
* Viral illness
* Kawasaki disease
163
What makes Kawasaki disease less likely in a patient with fever and rash?
Fever resolving after 4 days
164
What is the classic presentation of human herpesvirus 6 (HHV-6) infection?
High fevers (>39.5°C) for 3 to 5 days followed by pink noncoalescent macules on the trunk, face, and proximal extremities
165
What is another name for human herpesvirus 6 infection?
Roseola infantum or exanthem subitum
166
When do patients with HHV-6 generally appear well?
When the rash appears
167
What lymphadenopathy may be noted on examination in patients with roseola?
Postoccipital lymphadenopathy
168
What percentage of children with primary HHV-6 infection experience febrile seizures?
Approximately 10% to 15%
169
What is the most common cause of arboviral-acquired disease in the US?
West Nile virus (WNV)
## Footnote
WNV is the leading cause of such diseases in the United States.
170
What percentage of WNV infections are asymptomatic?
Approximately 80%
## Footnote
Most patients do not exhibit symptoms.
171
What is West Nile fever?
A self-limiting disease that typically lasts 3–10 days and manifests with fever, headaches, and a transient maculopapular rash
## Footnote
Symptoms appear on the trunks and extremities.
172
What are the symptoms of West Nile fever?
Fever, headaches, and a transient maculopapular rash
## Footnote
The rash is typically seen on the trunks and extremities.
173
What is the risk of neuroinvasive disease from WNV infection?
Up to 1% of patients
## Footnote
This includes severe manifestations such as meningitis and encephalitis.
174
What are the manifestations of neuroinvasive disease caused by WNV?
Fever and meningitis, encephalitis, or acute flaccid paralysis
## Footnote
These are serious complications of WNV infection.
175
What are the risk factors for neuroinvasive disease from WNV?
Age > 60 years, immunosuppression, comorbidities (e.g., hypertension, diabetes mellitus)
## Footnote
These factors increase the likelihood of severe disease.
176
What is the usual treatment for WNV infection?
Supportive treatment
## Footnote
The condition is typically self-limiting.
177
True or False: Most WNV infections lead to severe neurological illness.
False
## Footnote
Most infections are asymptomatic or result in mild illness.
178
Fill in the blank: WNV infection can lead to a _______ disease that manifests with fever and neurological symptoms.
neuroinvasive
## Footnote
This includes serious conditions such as meningitis and encephalitis.
179
How long does West Nile fever typically last?
3–10 days
## Footnote
It is a self-limiting condition.
180
What are the initial symptoms of disseminated gonococcal infection?
Fever, chills, malaise
## Footnote
These symptoms typically precede more specific manifestations.
181
What are the main presentations after fever resolves in disseminated gonococcal infection?
Triad of tenosynovitis, dermatitis, polyarthralgias or frank arthritis
## Footnote
Overlap in these presentations is frequent.
182
What does tenosynovitis generally affect?
Multiple tendons at once
## Footnote
This condition is characterized by inflammation of the tendon sheath.
183
How does dermatitis present in disseminated gonococcal infection?
Transient pustular or vesicular skin lesions
## Footnote
These skin manifestations are typically few in number.
184
What happens to patients who initially present with the triad without treatment?
Progress to joint involvement
## Footnote
Joint involvement is a common progression in untreated cases.
185
Which joints are most commonly affected by arthritis in disseminated gonococcal infection?
Knees, wrists, ankles
## Footnote
This can occur in a monoarticular or asymmetric polyarticular fashion.
186
What is the typical method for diagnosing disseminated gonococcal infection?
Positive blood or synovial fluid culture for Neisseria gonorrhoeae
## Footnote
These cultures are only positive in about 50% of cases.
187
What other cultures or tests are important for diagnosing disseminated gonococcal infection?
Vaginal, rectal, pharyngeal cultures, or nucleic acid amplification tests (NAATs)
## Footnote
These tests can be positive in 50% to 80% of patients, even if asymptomatic.
188
Why is testing local sites critical for diagnosis in disseminated gonococcal infection?
Synovial fluid Gram stain may be negative
## Footnote
Testing local sites helps confirm diagnosis when other tests are inconclusive.
189
What should synovial fluid be examined for in suspected cases of disseminated gonococcal infection?
N. gonorrhoeae by NAAT
## Footnote
NAAT can provide a more sensitive detection method for this pathogen.
190
What is a limitation of serological studies for syphilis?
They can miss early primary syphilis, as antibodies do not develop until 1–4 weeks after lesions appear.
## Footnote
Antibodies may not be detectable immediately after infection.
191
What testing algorithms are used to confirm a syphilis diagnosis?
Syphilis testing algorithms combine nontreponemal and treponemal tests.
## Footnote
These algorithms enhance diagnostic accuracy.
192
What clinical factors should be considered when interpreting syphilis test results?
Clinical features, risk factors, treatment history.
## Footnote
Context is crucial for accurate interpretation.
193
What is a key consideration regarding serologic testing in previously treated syphilis patients?
Serologic testing may remain positive.
## Footnote
This can complicate the interpretation of current infections.
194
What are the indications for nontreponemal tests (NTT)?
* Initial screening
* Monitoring response to treatment
* Assessing for syphilis reinfection
## Footnote
NTTs are valuable for both diagnosis and management.
195
What is the mechanism of nontreponemal tests (NTT)?
Quantitative detection of antibodies against lipoidal antigens, e.g., cardiolipin.
## Footnote
This reflects an immune response to syphilis.
196
What are the most commonly used nontreponemal tests?
* Rapid plasma reagin (RPR)
* Venereal Disease Research Laboratory test (VDRL)
## Footnote
RPR is the most widely used, while VDRL is often used for neurosyphilis.
197
What is the accuracy of nontreponemal tests in detecting primary syphilis?
Highly sensitive but nonspecific; positive in ∼ 62–78% of patients with primary syphilis.
## Footnote
This indicates variability in test performance.
198
What are potential causes of false-negative results in nontreponemal tests?
* Early primary syphilis
* Prozone phenomenon
* Longstanding untreated syphilis with seroreversion
## Footnote
These factors can obscure true infection status.
199
What are potential causes of false-positive results in nontreponemal tests?
* Autoimmune diseases (e.g., systemic lupus erythematosus, rheumatoid arthritis)
* Infections (e.g., malaria, leprosy, Epstein-Barr virus, viral hepatitis)
* Rheumatic fever
* Pregnancy
* Prescription drugs (e.g., chlorpromazine, procainamide)
* Intravenous drug use
## Footnote
False positives can arise from various non-syphilitic conditions.
200
What happens to nontreponemal test (NTT) titers after infection?
NTT titers can undergo seroreversion and convert to negative even if syphilis is not treated.
## Footnote
This complicates the monitoring of treatment success.
201
What is the mechanism of treponemal tests (TT)?
Qualitative detection of antibodies to treponemal antigens.
## Footnote
TTs are specific for Treponema pallidum.
202
What are the indications for treponemal tests (TT)?
* Initial screening
* Confirmatory test in the standard testing algorithm
## Footnote
TTs provide definitive evidence of infection.
203
What are common types of treponemal tests?
* Fluorescent treponemal antibody absorption test (FTA-ABS)
* Treponema pallidum particle agglutination (TPPA)
* IgG/IgM immunoassay (enzyme or chemiluminescence)
## Footnote
These tests vary in methodology but serve similar diagnostic purposes.
204
What is the accuracy of treponemal tests in new infections?
High sensitivity and specificity.
## Footnote
TTs are reliable for confirming recent infections.
205
What are potential causes of false-negative results in treponemal tests?
Early primary syphilis.
## Footnote
Timing of testing is critical for accurate results.
206
What are potential causes of false-positive results in treponemal tests?
* Inflammatory diseases (e.g., systemic lupus erythematosus)
* Infections (e.g., Lyme disease)
## Footnote
Similar to NTTs, TT results can be influenced by other conditions.
207
What happens to treponemal test (TT) titers after infection?
TT titer typically stays positive indefinitely.
## Footnote
This characteristic is important for historical infection tracking.
208
What is Kaposi sarcoma (KS) typically associated with?
HIV infection
209
In patients with HIV, KS typically occurs with a CD4 count of less than _______.
<150 cells/mm3
210
What is the reference range for CD4 count?
400–1600 cells/mm3
211
What viral load is associated with the occurrence of KS in HIV patients?
>10,000 copies/mL
212
True or False: HIV-associated KS can occur in patients with high CD4-cell count and low viral load.
True
213
KS has been reported in patients on long-term _______ therapy.
antiretroviral
214
What is Trimethoprim-sulfamethoxazole (TMP-SMX) used for in VIH patients?
Prophylaxis for Pneumocystis jirovecii pneumonia (PCP) and toxoplasmosis in HIV patients
215
In patients with HIV and a CD4+ count < 200/mm3, TMP-SMX is used to prevent which condition?
Pneumocystis jirovecii pneumonia (PCP)
216
In patients with HIV and a CD4+ count < 100/mm3, TMP-SMX is used to prevent which condition?
Toxoplasmosis
217
What alternatives can be administered to patients allergic to TMP-SMX?
Oral dapsone or atovaquone
218
What may be used if none of the other prophylactic agents are available?
Aerosolized pentamidine
219
Fill in the blank: TMP-SMX is used as prophylaxis for Pneumocystis jirovecii pneumonia (PCP) in patients with HIV and a CD4+ count < _______.
200/mm3
220
Fill in the blank: TMP-SMX is used as prophylaxis for toxoplasmosis in patients with HIV and a CD4+ count < _______.
100/mm3
221
True or False: TMP-SMX is the only option for prophylaxis in HIV patients.
False
222
What is the treatment recommendation for patients with chronic hepatitis B virus infection who test negative for hepatitis B e antigen?
Treatment is recommended if the HBV viral load is greater than 2000 IU/mL and the alanine aminotransferase level is greater than twice the upper limit of normal.
223
What are the criteria for a chronic hepatitis B virus patient to be a candidate for treatment?
HBV viral load greater than 2000 IU/mL and alanine aminotransferase level greater than twice the upper limit of normal.
224
What are the first-line oral antiviral therapies for chronic HBV infection?
Tenofovir or entecavir.
225
Fill in the blank: First-line antiviral therapy for chronic hepatitis B virus infection consists of either _______ or _______.
tenofovir or entecavir.
226
True or False: Entecavir is a first-line treatment for chronic hepatitis B virus infection.
True.
227
What is the significance of alanine aminotransferase levels in assessing treatment candidacy for chronic hepatitis B?
Levels must be greater than twice the upper limit of normal.
228
What is considered a high HBV viral load in the context of treatment candidacy?
Greater than 2000 IU/mL.
229
What does PPSV23 stand for?
Pneumococcal polysaccharide vaccine
230
What type of bacteria does PPSV23 protect against?
Streptococcus pneumonia
231
What is the most common cause of sepsis in children with sickle cell disease?
Streptococcus pneumonia
232
What condition do children with sickle cell disease develop due to recurrent splenic infarction?
Functional asplenia
233
At what age do children with sickle cell disease typically develop functional asplenia?
By the age of 4
234
Why are children with sickle cell disease at increased risk of infection?
Due to functional asplenia and increased risk of infection with encapsulated organisms
235
Fill in the blank: The pneumococcal polysaccharide vaccine prevents infection with _______.
Streptococcus pneumonia
236
True or False: Functional asplenia increases the risk of infection with encapsulated organisms.
True
237
What are the initial symptoms of Bordetella pertussis infection?
Malaise, rhinorrhea, and cough
## Footnote
This phase is known as the catarrhal phase.
238
What characterizes the paroxysmal phase of Bordetella pertussis infection?
Severe paroxysms of a dry cough
## Footnote
This phase follows the initial symptoms.
239
What is the recommended time frame for treatment initiation after cough onset for patients older than 1 year?
Within 3 weeks
## Footnote
This recommendation is made by the Centers for Disease Control and Prevention.
240
What effect does antibiotic therapy have on Bordetella pertussis transmission?
Decreases further transmission
## Footnote
However, it may not improve the duration or severity of symptoms if started later.
241
What is the treatment of choice for Bordetella pertussis infection?
A 5–7-day course of a macrolide antibiotic
## Footnote
Examples include azithromycin or clarithromycin.
242
How long should erythromycin be administered for Bordetella pertussis infection?
14 days
## Footnote
Erythromycin is an acceptable alternative to macrolides.
243
True or False: A patient with a history of cough paroxysms suspected to have B. pertussis infection should receive treatment with a macrolide antibiotic.
True
## Footnote
This is a key learning point regarding treatment.
244
What should be performed for any patient that meets the suspected case definition for pertussis?
Confirmatory studies
## Footnote
This includes various diagnostic tests based on the duration since symptom onset.
245
What are the preferred diagnostic tests for pertussis in the first 1-4 weeks since symptom onset?
PCR ± culture
## Footnote
These tests are recommended to confirm a suspected case of pertussis.
246
What diagnostic test should be considered between 4-12 weeks since cough onset?
Serum sample for serology
## Footnote
This is appropriate for cases that are beyond the acute phase.
247
What is a common finding in infants and young children with pertussis?
Lymphocyte-predominant leukocytosis
## Footnote
An absolute lymphocyte count of > 20,000 cells/μL suggests a poor prognosis.
248
What are the symptoms that indicate a suspected case of pertussis?
Cough with ≥ 1 of the following:
* Paroxysmal coughing
* Whooping on inspiration
* Posttussive vomiting
* Apnea
## Footnote
Additional factors include known contact with a confirmed case or living in an outbreak area.
249
What does the presence of fever suggest in a patient suspected of having pertussis?
An alternative diagnosis
## Footnote
Fever is not a typical symptom of pertussis.
250
What is the preferred test for diagnosing pertussis?
PCR
## Footnote
It has high sensitivity and rapid results, unaffected by antibiotic therapy or previous vaccination.
251
What specimen collection method is preferred for PCR testing in suspected pertussis cases?
Nasopharyngeal swab
## Footnote
An alternative method is saline nasopharyngeal aspirate.
252
What is considered the gold standard for pertussis diagnosis?
Bacterial culture
## Footnote
It has 100% specificity but is limited by long growth time and low sensitivity.
253
What are the indications for using bacterial culture in pertussis diagnosis?
Alternative when PCR is not available and for strain identification
## Footnote
It is used in addition to PCR.
254
What criteria must be met for serology testing in suspected pertussis cases?
4-12 weeks since cough onset, age ≥ 6 months, ≥ 1 year since last vaccination
## Footnote
Findings include increased IgG antibodies to pertussis toxin.
255
What does the CDC accept for disease reporting in pertussis cases?
Positive culture or PCR
## Footnote
Serology is suggested for use in outbreak settings but not accepted for reporting.
256
True or False: Direct fluorescent antibody testing and blood cultures are recommended for pertussis diagnosis.
False
## Footnote
These methods are not recommended due to low specificity and sensitivity.
